The invention relates to coin processing equipment and, more particularly, to coin sorters.
In Zwieg et al., U.S. Pat. No. 5,992,602, coins were identified by using an inductive sensor to take three readings as each coin passed through a coin detection station and these readings were compared against prior calibrated limits for the respective denominations.
Optical sensing of coins in coin handling equipment has been employed in Zimmermann, U.S. Pat. No. 4,088,144 and Meyer, U.S. Pat. No. 4,249,648. Zimmermann discloses a rail sorter with a row of photocells. Zimmermann does not disclose repeated measurements of a coin dimension as it passes the array, but suggests that there may have been a single detection of the largest dimension of the coin based on the number of photocells covered by a coin as it passes. Zimmermann does not disclose the details of processing any coin sensor signals derived from its photosensor.
Meyer, U.S. Pat. No. 4,249,648, discloses optical imaging of coins in a bus token collection box in which repeated scanning of chord length of a coin is performed by a 256-element linear light sensing array. Light is emitted through light transmissive walls of a coin chute and received on the other side of the coin chute by the light sensing array. The largest chord length is compared with stored acceptable values in determining whether to accept or reject the coin.
It has also been known in the prior art to detect invalid coins using various types of inductive sensors. Examples of these are disclosed in Hayes, U.S. Pat. No. 5,568,854 and Hayes, U.S. Pat. No. 5,351,798 and Bernier, U.S. Pat. No. 6,148,947.
The invention relates to a sensor for a coin sorter and methods for rapidly and accurately identifying coins having up to at least eighteen different coin specifications.
The sensor utilizes an optical sensor to detect coin size, and also utilizes a core alloy sensor, a surface alloy sensor and edge alloy/thickness sensor to develop multiple parameters for accepting or rejecting a coin.
In one embodiment, the sensor utilizes five microcontrollers to read in data for size, a surface alloy, a core alloy, and an edge alloy/thickness parameter. In another embodiment only size is measured.
One object of the present invention is to use a coin detection sensor that will process up to 4500 coins per minute.
Another object of the invention is to provide a rotatable light transmissive coin moving member. Such a large light transmissive member has not been seen in the prior art.
Another object of the present invention is to provide an enhanced type of contactless coin sensor assembly for both coin counting and for detection of invalid coins for offsorting.
Another object of the invention is to provide a ceramic coin path insert over which the coins pass, when passing through the sensor, which coin path insert avoids absorption of metal from the coins.
In one embodiment light is passed through a sapphire window in the coin path insert to be received by a linear sensing array with 768 elements. In another embodiment, the upper surface of the coin path insert is formed by an integral, transparent, sapphire element.
The optical imaging sensor using a hardware logic circuit to rapidly measure a coin dimension a number of times, so that data is not skewed by nicks in the rim of the coins. The alloy sensors are arranged to take readings from the body of the coins and inward from the edges of coins in response to the coin covering or uncovering a trigger point.
While the present invention is disclosed in a preferred embodiment based on Zwieg et al., U.S. Pat. No. 5,992,602, the invention could also be applied as a modification to other types of machines, including the other prior art described above.